The invention generally relates to resonant scanners, and relates in particular to taut-band resonant scanners that include an elongated stiff band that is held in tension to provide the resonance frequency for the scanner.
Conventional taut-band resonant scanners however, typically suffer from a variety of drawbacks. First, many conventional taut band resonant scanners include a certain amount of undesired wobble during use. Second, stress on the band is typically concentrated where the band attaches to the mirror mounting structure and/or the band clamping structure, and such concentrated stress may lead to failure of the band at those locations.
Third, the band-load combinations are fixed, so that a desired change in mirror dimension or frequency of operation typically requires replacement of the mirror, it's counter mass if any, the band, and often the entire structure leading to excess cost in manufacture and repair. Fourth, temperature changes during operation may have a significant negative impact on operation due to the varied thermal expansion of the individual components, which leads to a concomitant change in the operating natural frequency of the device.
Further, environmental corrosion also negatively impacts operation. For example, many conventional taut band resonant scanners employ clock spring steel for the band, but this material typically develops rust as well as stress corrosion cracking during use, which causes failure of the band long before the design lifetime is reached.
There is a need therefore, for a taut band resonant scanner that avoids or minimizes at least the above drawbacks.